A novel lectin was isolated from the seeds of Chenopodium quinoa. To achieve this end, the crude extract from the quinoa was submitted to two purification steps, Sephadex G50 and Mono Q. The hemagglutinating activity showed that this lectin agglutinates human erythrocytes. Its activity is inhibited by glucose and mannose, and remained stable under a wide range of pH levels and temperatures. The quinoa lectin was found to be a heterodimeric lectin of approximately 60 kDa, consisting of two subunits of approximately 25 kDa and 35 kDa. This lectin had its antimicrobial activity tested against several bacteria strains and effectively inhibited three strains. These strains were all Gram-negative, making this lectin a promising antimicrobial tool.Keywords: antimicrobial; Chenopodium quinoa; glucose/mannose-specific; lectin; seeds. Practical Application:The purification and characterization of this novel lectin allow its study for a diversity of applications such as antibacterial, anticancer, anti-inflammatory and biotechnology and its further use as drugs for human diseases.

A novel trypsin inhibitor of protease (CqTI) was purified from Chenopodium quinoa seeds. The optimal extracting solvent was 0.1M NaCl pH 6.8 (p < 0.05). The extraction time of 5h and 90 °C was optimum for the recovery of the trypsin inhibitor from C. quinoa seeds. The purification occurred in gel-filtration and reverse phase chromatography. CqTI presented active against commercial bovine trypsin and chymotrypsin and had a specific activity of 5,033.00 (TIU/mg), which was purified to 333.5-fold. The extent of purification was determined by SDS-PAGE. CqTI had an apparent molecular weight of approximately 12KDa and two bands in reduced conditions as determined by Tricine-SDS-PAGE. MALDI-TOF showed two peaks in 4,246.5 and 7,908.18m/z. CqTI presented high levels of essential amino acids. N-terminal amino acid sequence of this protein did not show similarity to any known protease inhibitor. Its activity was stable over a pH range (2-12), temperatures range (20-100 °C) and reducing agents.Keywords: purification; characterization; inhibitor of trypsin; Chenopodium quinoa; seeds. Practical Application:The purification and characterization of this novel trypsin inhibitor allow its study for a diversity of applications such as antibacterial, anticancer, anti-inflammatory and biotechnology and its further use as drugs for human diseases.

Humans need amino acids, especially the essential ones, which are obtained from the proteins ingested in the diet. With the rampant growth of the world population, it is necessary to increase the protein supplies, especially those of plant origin, which now play a major role as a food source. Leaves of ora-pronobis (Pereskia aculeata Miller) are a high quality protein source and have been used in the traditional cuisine of Minas Gerais for decades. However, it is important to analyze the anti-nutritional and/or toxic factors to consider the use of the plant leaves as an alternative source of nutrients. This work aimed to study the presence of proteic anti-nutritional factors, such as protease inhibitors and lectins, and to evaluate the "in vitro" digestibility throughout Tricine SDS-PAGE of these factors extracted from ora-pro-nobis (Pereskia aculeata Miller) leaves. The extraction of protease inhibitors and lectins from ora-pro-nobis leaves was performed in phosphate buffer. The partial purification of the fractions presenting activity of trypsin inhibitor and lectins was performed by ammonium sulfate precipitation and gel-filtration chromatography. The "in vitro" activity of the fractions with protease inhibitor and lectins, with or without heat treatment in the presence of digestive enzymes, showed that the cooking time of 1 minute was sufficient for protease inhibitors degradation. However, this time was not satisfactory for lectins, which remained resistant even after heating. This work shows that with proper cooking, ora-pro-nobis leaves can be used in the diet as a source of aminoacids. RESUMOO homem necessita na sua alimentação de aminoácidos, especialmente os essenciais, os quais são obtidos a partir das proteínas ingeridas na alimentação, que podem ser tanto de origem animal quanto vegetal. Com o crescimento desenfreado da população mundial será necessário multiplicar o suprimento de proteínas, principalmente aquelas de origem vegetal, que passam a desempenhar um papel de grande importância como fonte de alimento. As folhas de ora-pronobis (Pereskia aculeata Miller) são uma fonte protéica de alta qualidade e vem sendo utilizada na culinária mineira há décadas. Porém, para a utilização de folhas vegetais como fonte alternativa de nutrientes, é necessário o conhecimento da presença de fatores antinutricionais e/ou tóxicos que possam afetar o valor nutricional dos alimentos. Esse trabalho teve como objetivo realizar o estudo de fatores antinutricionais, inibidores de protease e lectinas, e avaliar a digestibilidade "in vitro" em SDS-PAGE de Tricina desses fatores extraídos das folhas de ora-pro-nobis (Pereskia aculeata Miller). Foi realizada a extração dos inibidores de protease e lectinas das folhas de ora-pro-nobis em solução tampão fosfato, seguida de precipitação de sulfato de amônia e parcial purificação das frações com atividade de inibidor em tripsina e lectinas, utilizando a coluna de separação por exclusão molecular. A digestibilidade "in vitro" das frações com atividade de inibição de p...

Chenopodium quinoa seeds have high protein content. The nutritional value of quinoa is superior compared with traditional cereals. Its essential amino acid composition is considered next to the ideal, and its quality matches that of milk proteins. In this study, the seed storage proteins from Chenopodium quinoa were extracted, fractionated, partially purified, and characterized. The structural characterization was performed by Tricine-SDS-PAGE and two-dimensional electrophoresis, and it confirmed the presence of proteins of molecular weight of 30 and 7kDa, probably corresponding to lectins and trypsin inhibitors, respectively. The functional characterization of these proteins evidenced their activity as antinutritional factors due to their in vitro digestibility. Quinoa proteins have an excellent amino acid composition with many essential amino acids. In vitro digestibility evaluation indicated that heat-treated samples showed a more complete digestion than the native state samples. Quinoa seeds can be an important cereal in human diet after adequate heat treatment.Keywords: Chenopodium quinoa; seeds; lectins; protease inhibitor; in vitro digestibility.Practical Application: SDS-PAGE to evaluate the effect of digestive enzymes in seed proteins.

Chenopodin is an 11S-type globulin purified from Chenopodium quinoa seeds, which can bind carbohydrates and hemagglutinating human erythrocytes. The present study aimed to evaluate the N-terminal structure of the heterodimeric Chenopodin and its effects in models of inflammation. Chenopodin presented two subunits on its structure and has N-terminal homology with other Chenopodin in 92%. Chenopodin decreased paw edema and neutrophil recruitment induced by carrageenan in mice. Concluding, we demonstrated that Chenopodin exhibits in vivo anti-inflammatory activity.